My 22 ft FourWinns Horizon used to do about 48 now she runs not more than 35 - 38 depending on fuel load, passengers etc. I maintain everything very well, just had all belts, plugs etc changed. The engine is fuel injected 351 King Cobra Ford. Just cant get her back to top speed and she doesnt pop my tubers and boarders up like she used to. The engine runs great and she never lets me down. Love this boat but need more speed? Thanks in advance for any suggestions.